MONDAY, Feb. 27 (HealthDay News) -- Rapid diagnostic influenza tests provide an accurate diagnosis, and their use during flu season could lead to earlier treatment for patients and help prevent the spread of the illness, two new studies suggest.
The 2012 flu season is just beginning and, despite the late start, is expected to sicken up to 5 million people worldwide, experts say. Most patients will recover, but up to 500,000 will die, with the youngest and oldest patients most vulnerable.
The two studies, published online in the Feb. 28 issue of the journal Annals of Internal Medicine, highlight the importance of prompt diagnosis and treatment.
Viral cultures are accurate in diagnosing flu but can take up to 10 days to provide results. Newer reverse transcriptase-polymerase chain reaction (RT-PCR) tests provide results much sooner but are expensive and require specialized equipment.
Rapid influenza diagnostic tests, which are inexpensive and easy to use in a doctor's office, are another option, but little was known about their accuracy.
In one study, researchers reviewed 159 published articles and found that rapid influenza diagnostic tests accurately diagnose flu, but are less accurate at ruling it out. This means that patients with a negative result would require follow-up testing with a viral culture or RT-PCR, the researchers said in a journal news release.
They said their results suggest that rapid diagnostic tests would be useful in clinical practice, especially when treating children and other patients at risk for flu-related complications. This includes people over 65, pregnant women and those with chronic health conditions such as asthma.
For patients diagnosed with flu, doctors may decide to begin treatment with antiviral drugs.
In the second study, researchers reviewed 74 published studies and found that early treatment with antiviral drugs (within 48 hours) may confer more benefits than later treatment.
The researchers tested four commonly prescribed antivirals, and said oral oseltamivir and inhaled zanamivir appeared to shorten duration of flu symptoms compared to no treatment.
The U.S. Centers for Disease Control and Prevention has more about seasonal flu.
-- Robert Preidt
SOURCE: Annals of Internal Medicine, news release, Feb. 24, 2012
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